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I have an Isuzu C-201 4 cylinder diesel engine that came from a ThermoKing refrigeration unit. It is an engine manufactured by Isuzu specifically for Thermoking, I dont believe it was made for anyone else. It even has the thermoking name cast into the block. and oil pan.

The problem is that I purchased this engine with the intentions of using it for a generator and/or pressure washer. This means it will need a power take off installed on it. It has what appears to be an SAE #6 bellhousing on it. There are 8 bolt holes and they are 11 1/4", center to center from one side to the other. These are the exact specs of an SAE #6 bellhousing. However the flyweel has six large (1/2"or 5/8") studs sticking out of it. I am unsure if the studs are removable or not, but it was used for some kind of a direct drive to the compressor when used on the refrigeration unit. I believe it was what is called a rubber block drive. Rubber bushings fit over the studs the compressor was then bolted to the engine. In order for a clutch to bolt up, the studs will have to be removed or a new flywheel installed.

One problem I ran into is that a Twin-Disc PTO dealer told me that an SAE 6 PTO uses either a 6" or a 7" clutch and said that the flywheel ring gear needed for the clutch would bolt onto the flywheel but said the flywheel bolts would need to be about 7 or 8 inches from center to center, one side to the other side. The bolt holes that ARE in the flywheel I have are (approximately, measured with a tape measure) 9.75" apart.

This means that there are no ring gears that will fit this flywheel. A new flywheel will be needed or I will need to use a larger PTO which will require a new bellhousing, and of course the larger PTO also costs more money. This engine is only 28hp, it doesn't need a bigger PTO. I dont even know if the bolt pattern on the back of this engine will take a different bellhousing - the bellhousing on this engine is the same one that thermo king used.

I am in need of a little help here. I dont know where to go from here. I am having a hard time finding a #6 PTO used, and a new one is $900, which is 9 times more than what I paid for the engine!! Even if I had an SAE 6 PTO I dont think it would mate up to this flywheel and I dont know if they make a flywheel for this purpose or not. I do think I remember hearing that thermoking made generator sets using these engines (odd, since they are an over the road refrigeration unit manufacturer) but I dont know if they used a power take off on them or if they were direct drive too.

I really have a hard time believing that they would build this engine with such a totally unique bolt pattern that it could not possibly be used with anything other than the thermoking compressors. Surely there will be parts to mate this up to a PTO so I can use it for my intended purpose?

How does (did) the engine start if there is no ring gear on the flywheel?
What is the diameter of your flywheel?
If there are studs sticking out of the flywheel, they can be removed.
Flywheels are not hardened exotic alloys. Should be able to drill & tap anywhere you need to attach a clutch pressure plate assy and make it work for you.

Sorry, I should be more clear on that. There is the ring gear on the outside of the flywheel for the starter, but the rockford/twin disc PTO's use another ring gear that bolts ON the flywheel. The clutch disc has a bunch of teeth on it that mesh with the ring gear on the flywheel to drive the PTO, its basically a big gear made out of fiber. When you hit the clutch on the PTO it squeezes the clutch disc and makes a solid connection. When you release the clutch, the flywheel and clutch disc continue to rotate, but the PTO freewheels. Its hard to explain so I hope that makes sense.

Anyways, the flywheel is like 11 inches, something like that. The clutch used on an SAE 6 PTO is either 6 or 7 inches and the holes used to bolt the ring gear for that clutch to the flywheel need to be about 7 or 8 inches apart from center to center. The holes on this flywheel are about 9.75" apart, which means this flywheel wont take this clutch. I might be able to make it take this clutch but I dont know. It would take some machine work . The pilot bearing hole in the middle of the flywheel is not large enough for the PTO tip to fit in. Plus the clutch holes would need to be perfect drilled and tapped, no room for any error or the clutch would not rotate in a perfect circle.

Torque, that engine was specifically specced for Thermo-King by Isuzu. Prior to them buying engines from Isuzu they used diesels made by Mercedes-Benz. Basicly Mercedes modified their OM636 engine from the old 180D as it had already been used in tractors, generators, boats,fork lifts, etc. Trouble is most engine components except the Injector pump were on the back side of the engine when working on a T.K unit and made life difficult. When Thermo-King wanted a fresh power plant Mercedes wouldnt build one specifically to Thermo-Kings specs and said " take what we have or leave it" so they went with Isuzu for many years. I think all new trailler units have 4 cyl Yanmars now. Thermo-King did make generators, for THEIR units. These were undermount generators on trailers made for over seas cargo containers that had flush mount Thermo-Kings in them or rail-mode trailers,etc that were elec only. I would think a machine shop could face off that flywheel and make a plate to adapt a coupling for it.

As was said earlier, you don't really need a clutch for a generator or pressure washer.

When I put the Perkins 4.154 in my '50 Chevy, I had the SAE flywheel turned then drilled and tapped to accept the Chevy clutch disk and pressure plate. I also made an adapter so I could use the Chevy pilot bearing and made a bellhousing/converter for the Chevy tranny. It wasn't much of an engineering stretch to do.

If you don't need a clutch, just work out a way to couple the generator to the flywheel and you're in.

Does the flywheel have a flat face like a clutch would need? Do you need a clutch, or just a drive plate? Most direct drive power units use a solid plate bolted to the flywheel w/a splined hub in the center. I would think you could find or have such a plate made. Or, engines like irrigation pump units use a u-joint yoke bolted on w/the flywheel bolts to drive right to the pump. Just some ideas...

I have never known an engine manufacturer selling in N. America not to offer standard SAE flywheels and housings. If your particular engine and flywheel doesn't conform to SAE standards, I am sure Isuzu can offer one. It is a matter of finding one reasonably priced. Most generator manufacturers conform to SAE# drive dimensions for their frame and flex plate coupling bolt circles. I suggest you contact an Isuzu distributor to find out exactly what rear end is on your spec# engine, and what changes you need for the clutch PTO you have selected.

The clutch/PTO would be used to disconnect the load from the engine when not needed. I dont know that I really HAVE to have that, but it'd be nice. I could probably find a two groove pulley to go on the crankshaft upfront, and I could use that for the generator but I dont know that I want to put the pressure washer pump up front. A steel plate with a shaft in the middle of it would probably be fine and then have some pulleys attached to it. Id be concerned then about there being no bearings to support the side load that would be on the shaft then, since it will have to stick out several inches to clear the bellhousing and such. I've attached a picture of the type of PTO i am interested in using. I feel that some people aren't quite understanding what I am trying to do. Some of you do tho, but not everyone is used to industrial engines.

There are a few things you need to know about the Twin Disc clutch.They are not made for a soft slip,when you engage them you need to do it as soon as you can.Its a "over center" clutch engagement and easy to adjust (just pull back on the pin and rotate to the right to tighten).If you run for a prolonged period while disengaged they may heat up and burn up.You need to know if your clutch will handle the engine torque.Twin Disc makes adapters that will let you go from one size bell housing to another.They have a three piece drive disc in the single plate clutch.If you have to much engine torque for your clutch,you can get an adapter and go to a bigger clutch.The Twin disc or Rockford people should supply you with specs such as drawings for flywheel depth, pilot bearing sizes and depths drive ring bolt patterns,etc.and horspower/torque/R.P.M. figures.They even make two and three plate clutches, so you can run more torque in the smaller bell housings.If you don't need a clutch,don't run one.Good luck.

The small 6 inch clutch will more than handle the torque of this little engine. Its 28hp and something like 68 ft lb? I wouldnt be running it long without the clutch engaged probably but who knows. I probably dont NEED a clutch, I just thought it might be better to have one. Is a drive plate/shaft something I will have to have made up or can one be bought somewhere?

A common way is to make a "stub shaft" that bolts to the flywheel and has a 1 or 1 1/4" shaft. In order to use a belt or any side load you would need a bearing as the engine bearings aren't designed to take much side load. If direct driveing, you can add a "Lovejoy" or other flex coupling driectly to the stub shaft.

Yea thats why I was wanting a PTO. It think it'd be easier, basically a bolt on and you can turn it on and off. And it will take the side load.

I cant direct drive this engine because it makes its peak power (as configured from thermo king anyways) at 2200rpm - My pressure washer pump needs only 1200 rpm. It needs pulleys to reduce the RPMs. I dont think this engine would produce enough HP at 1200 rpm to run this pump. It needs 20+ to run full volume and pressure. 1200 rpm is about half of the 2200 where it makes peak power at so it would probably make half of 28 hp which would be 14. 14 diesel HP might be enough but it'd be pushing it. Id rather not try it to find out first.

I found your post the other night while researching a generator project myself. The Isuzu diesels found in P'ups and Luv's are C223 engines and many parts are interchangeable with the C201 TK engine. I think the flywheels have the same bolt circle. This would give you the flat surface and threaded holes for the clutch. Most of these trucks have been exported so you might have some trouble locating one. I saved one from a mid 80's truck. I'll try to dig it out, compare it to the C201 TK flywheel and get some measurements. Just to let you know the 6 drive pins are removable, but you'll most likely need to remove the flywheel to drive them from the backside. You'll need to remove the flywheel housing in order to get the flywheel off. Don't lose the shims between the housing and oil pan.

Just to add my 2 cents worth on stub shafts and side loads. Over 30 years ago we put a Saab V4 on our buzzsaw using a stub shaft and belt drive with 3 vbelts going to the original flat belt pulley. This unit has cut lots of wood with no problems over the years.
We decided that the side load would be less than the load from the pistons pushing on the crank. It did work out that the belts pull up on the crank which counteracts the piston load.
Also remember that all those old flywheel engines ran equipment from a pulley well outboard of the main bearings and the cranks were much smaller than auto engine cranks.

I have an Isuzu C-201 4 cylinder diesel engine that came from a ThermoKing refrigeration unit. It is an engine manufactured by Isuzu specifically for Thermoking, I dont believe it was made for anyone else. It even has the thermoking name cast into the block. and oil pan.

The problem is that I purchased this engine with the intentions of using it for a generator and/or pressure washer. This means it will need a power take off installed on it. It has what appears to be an SAE #6 bellhousing on it. There are 8 bolt holes and they are 11 1/4", center to center from one side to the other. These are the exact specs of an SAE #6 bellhousing. However the flyweel has six large (1/2"or 5/8") studs sticking out of it. I am unsure if the studs are removable or not, but it was used for some kind of a direct drive to the compressor when used on the refrigeration unit. I believe it was what is called a rubber block drive. Rubber bushings fit over the studs the compressor was then bolted to the engine. In order for a clutch to bolt up, the studs will have to be removed or a new flywheel installed.

One problem I ran into is that a Twin-Disc PTO dealer told me that an SAE 6 PTO uses either a 6" or a 7" clutch and said that the flywheel ring gear needed for the clutch would bolt onto the flywheel but said the flywheel bolts would need to be about 7 or 8 inches from center to center, one side to the other side. The bolt holes that ARE in the flywheel I have are (approximately, measured with a tape measure) 9.75" apart.

This means that there are no ring gears that will fit this flywheel. A new flywheel will be needed or I will need to use a larger PTO which will require a new bellhousing, and of course the larger PTO also costs more money. This engine is only 28hp, it doesn't need a bigger PTO. I dont even know if the bolt pattern on the back of this engine will take a different bellhousing - the bellhousing on this engine is the same one that thermo king used.

I am in need of a little help here. I dont know where to go from here. I am having a hard time finding a #6 PTO used, and a new one is $900, which is 9 times more than what I paid for the engine!! Even if I had an SAE 6 PTO I dont think it would mate up to this flywheel and I dont know if they make a flywheel for this purpose or not. I do think I remember hearing that thermoking made generator sets using these engines (odd, since they are an over the road refrigeration unit manufacturer) but I dont know if they used a power take off on them or if they were direct drive too.

I really have a hard time believing that they would build this engine with such a totally unique bolt pattern that it could not possibly be used with anything other than the thermoking compressors. Surely there will be parts to mate this up to a PTO so I can use it for my intended purpose?

I am attempting the same thing. How did your project work out? I have a strong argument in favor of a clutch over a direct drive on this engine. When you start the engine ther is a severe hammering effect until it reaches a certain RPM. I have twisted off several different shafts from the hammering and have decided to install a clutch if possible.